Analysis of historic rammed earth construction

Abstract

Rammed earth is an ancient construction technique which has recently become popular for sustainable building. Soil is compacted in removable formwork to make a homogeneous wall. A lack of experimental evidence and a poor fundamental understanding means that current design guidelines are highly conservative and inappropriate for the analysis of historic rammed earth buildings. This thesis shows that rammed earth can be viewed in a geotechnical engineering framework and that doing so helps to explain many aspects of the material behaviour. Rammed earth walls were built and tested in the laboratory then modelled using techniques available to practising engineers. Unsaturated soil mechanics was considered useful in explaining much of the behaviour of rammed earth. This was investigated through a series of uniaxial compression tests and the results are explained using unsaturated soil mechanics. Visits to Spain and India were made to investigate rammed earth in the field. Historic construction techniques, modes of failure and repair strategies were studied. The unsaturated nature of rammed earth is used to explain modes of failure and to suggest the most appropriate repair strategies